1. Field of the Invention
The present invention relates to a method for low-speed reproducing in a video cassette recorder (VCR). More particularly, it relates to a method for low-speed reproducing in a video cassette recorder (VCR) capable of reproducing a continuous time varying image in which a noise, or an unstable vibration of the screen is prevented when reproducing at a low speed of 2/3, 1/2, etc. of the normal speed in the VCR.
2. Description of the Related Art
Generally, a video cassette recorder (VCR) is an apparatus for recording and reproducing a video and an audio signal recorded on a recording medium, i.e., a video cassette tape. The VCR can reproduce the recorded video signal at a normal, low or high speed, or can stop reproducing the signal.
The servo system of the VCR is divided into a drum servo which controls the rotation of a head, and a capstan servo which controls the track and maintains the running speed of the recording medium. Specifically, the capstan servo controls the phase and speed of the capstan motor so that the head which is allotted to each channel can accurately reproduce the video signal of the relevant channel. The capstan servo also regularly maintains the running speed of the recording medium when reproducing or recording. The rotation speed of the capstan motor is controlled by obtaining a capstan speed error voltage from a capstan frequency generator (CFG) signal corresponding to the running speed of the recording medium. In the case of a low-speed reproducing, a temporary stop, a classifying operation, etc., a slow step signal outputted from the microcomputer is applied to the capstan motor.
The phase of the capstan motor is controlled by adding the capstan speed control voltage to a capstan phase error voltage which is obtained by comparing the frequency of a control signal with a reference frequency when reproducing.
In the case of a conventional 2-head VCR, a first head (channel 1) and a second head (channel 2) are arrayed at the periphery of the head drum facing each other apart by 180 degrees. Moreover, in order to enhance the recording density in the conventional recording medium, a method for obliquely recording the video signal in the recording medium per unit of field is applied. Here, the video signal is recorded in alternating turns in a first field (field 1) corresponding to channel 1 and in a second field (field 2) corresponding to channel 2. The signals recorded in field 1 and field 2 are recorded using an Azimuth recording method in order to prevent the signals from disturbing each other.
When the recording medium is run at a predetermined speed by the capstan motor and the head drum is rotated at a predetermined speed by a spindle motor, the first head reproduces the video signal recorded in field 1 (channel 1) and the second head reproduces the video signal recorded in field 2 (channel 2) according to the head switching pulse signal. By composing the signals recorded in fields 1 and 2, it is possible to reproduce the video signal of one frame.
In addition, in the conventional low-speed reproducing method, a stopped (paused) screen is continuously reproduced irregularly by simply rotating the capstan motor with the slow step method. In this case, the reproduced screen is stopped once per a predetermined period.